1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 SiFive
*/
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/ptdump.h>
#include <asm/ptdump.h>
#include <linux/pgtable.h>
#include <asm/kasan.h>
#define pt_dump_seq_printf(m, fmt, args...) \
({ \
if (m) \
seq_printf(m, fmt, ##args); \
})
#define pt_dump_seq_puts(m, fmt) \
({ \
if (m) \
seq_printf(m, fmt); \
})
/*
* The page dumper groups page table entries of the same type into a single
* description. It uses pg_state to track the range information while
* iterating over the pte entries. When the continuity is broken it then
* dumps out a description of the range.
*/
struct pg_state {
struct ptdump_state ptdump;
struct seq_file *seq;
const struct addr_marker *marker;
unsigned long start_address;
unsigned long start_pa;
unsigned long last_pa;
int level;
u64 current_prot;
bool check_wx;
unsigned long wx_pages;
};
/* Address marker */
struct addr_marker {
unsigned long start_address;
const char *name;
};
/* Private information for debugfs */
struct ptd_mm_info {
struct mm_struct *mm;
const struct addr_marker *markers;
unsigned long base_addr;
unsigned long end;
};
enum address_markers_idx {
FIXMAP_START_NR,
FIXMAP_END_NR,
PCI_IO_START_NR,
PCI_IO_END_NR,
#ifdef CONFIG_SPARSEMEM_VMEMMAP
VMEMMAP_START_NR,
VMEMMAP_END_NR,
#endif
VMALLOC_START_NR,
VMALLOC_END_NR,
PAGE_OFFSET_NR,
#ifdef CONFIG_KASAN
KASAN_SHADOW_START_NR,
KASAN_SHADOW_END_NR,
#endif
#ifdef CONFIG_64BIT
MODULES_MAPPING_NR,
KERNEL_MAPPING_NR,
#endif
END_OF_SPACE_NR
};
static struct addr_marker address_markers[] = {
{0, "Fixmap start"},
{0, "Fixmap end"},
{0, "PCI I/O start"},
{0, "PCI I/O end"},
#ifdef CONFIG_SPARSEMEM_VMEMMAP
{0, "vmemmap start"},
{0, "vmemmap end"},
#endif
{0, "vmalloc() area"},
{0, "vmalloc() end"},
{0, "Linear mapping"},
#ifdef CONFIG_KASAN
{0, "Kasan shadow start"},
{0, "Kasan shadow end"},
#endif
#ifdef CONFIG_64BIT
{0, "Modules/BPF mapping"},
{0, "Kernel mapping"},
#endif
{-1, NULL},
};
static struct ptd_mm_info kernel_ptd_info = {
.mm = &init_mm,
.markers = address_markers,
.base_addr = 0,
.end = ULONG_MAX,
};
#ifdef CONFIG_EFI
static struct addr_marker efi_addr_markers[] = {
{ 0, "UEFI runtime start" },
{ SZ_1G, "UEFI runtime end" },
{ -1, NULL }
};
static struct ptd_mm_info efi_ptd_info = {
.mm = &efi_mm,
.markers = efi_addr_markers,
.base_addr = 0,
.end = SZ_2G,
};
#endif
/* Page Table Entry */
struct prot_bits {
u64 mask;
u64 val;
const char *set;
const char *clear;
};
static const struct prot_bits pte_bits[] = {
{
.mask = _PAGE_SOFT,
.val = _PAGE_SOFT,
.set = "RSW",
.clear = " ",
}, {
.mask = _PAGE_DIRTY,
.val = _PAGE_DIRTY,
.set = "D",
.clear = ".",
}, {
.mask = _PAGE_ACCESSED,
.val = _PAGE_ACCESSED,
.set = "A",
.clear = ".",
}, {
.mask = _PAGE_GLOBAL,
.val = _PAGE_GLOBAL,
.set = "G",
.clear = ".",
}, {
.mask = _PAGE_USER,
.val = _PAGE_USER,
.set = "U",
.clear = ".",
}, {
.mask = _PAGE_EXEC,
.val = _PAGE_EXEC,
.set = "X",
.clear = ".",
}, {
.mask = _PAGE_WRITE,
.val = _PAGE_WRITE,
.set = "W",
.clear = ".",
}, {
.mask = _PAGE_READ,
.val = _PAGE_READ,
.set = "R",
.clear = ".",
}, {
.mask = _PAGE_PRESENT,
.val = _PAGE_PRESENT,
.set = "V",
.clear = ".",
}
};
/* Page Level */
struct pg_level {
const char *name;
u64 mask;
};
static struct pg_level pg_level[] = {
{ /* pgd */
.name = "PGD",
}, { /* p4d */
.name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD",
}, { /* pud */
.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
}, { /* pmd */
.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
}, { /* pte */
.name = "PTE",
},
};
static void dump_prot(struct pg_state *st)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(pte_bits); i++) {
const char *s;
if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val)
s = pte_bits[i].set;
else
s = pte_bits[i].clear;
if (s)
pt_dump_seq_printf(st->seq, " %s", s);
}
}
#ifdef CONFIG_64BIT
#define ADDR_FORMAT "0x%016lx"
#else
#define ADDR_FORMAT "0x%08lx"
#endif
static void dump_addr(struct pg_state *st, unsigned long addr)
{
static const char units[] = "KMGTPE";
const char *unit = units;
unsigned long delta;
pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT " ",
st->start_address, addr);
pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa);
delta = (addr - st->start_address) >> 10;
while (!(delta & 1023) && unit[1]) {
delta >>= 10;
unit++;
}
pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
pg_level[st->level].name);
}
static void note_prot_wx(struct pg_state *st, unsigned long addr)
{
if (!st->check_wx)
return;
if ((st->current_prot & (_PAGE_WRITE | _PAGE_EXEC)) !=
(_PAGE_WRITE | _PAGE_EXEC))
return;
WARN_ONCE(1, "riscv/mm: Found insecure W+X mapping at address %p/%pS\n",
(void *)st->start_address, (void *)st->start_address);
st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
}
static void note_page(struct ptdump_state *pt_st, unsigned long addr,
int level, u64 val)
{
struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
u64 pa = PFN_PHYS(pte_pfn(__pte(val)));
u64 prot = 0;
if (level >= 0)
prot = val & pg_level[level].mask;
if (st->level == -1) {
st->level = level;
st->current_prot = prot;
st->start_address = addr;
st->start_pa = pa;
st->last_pa = pa;
pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
} else if (prot != st->current_prot ||
level != st->level || addr >= st->marker[1].start_address) {
if (st->current_prot) {
note_prot_wx(st, addr);
dump_addr(st, addr);
dump_prot(st);
pt_dump_seq_puts(st->seq, "\n");
}
while (addr >= st->marker[1].start_address) {
st->marker++;
pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
st->marker->name);
}
st->start_address = addr;
st->start_pa = pa;
st->last_pa = pa;
st->current_prot = prot;
st->level = level;
} else {
st->last_pa = pa;
}
}
static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
{
struct pg_state st = {
.seq = s,
.marker = pinfo->markers,
.level = -1,
.ptdump = {
.note_page = note_page,
.range = (struct ptdump_range[]) {
{pinfo->base_addr, pinfo->end},
{0, 0}
}
}
};
ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL);
}
void ptdump_check_wx(void)
{
struct pg_state st = {
.seq = NULL,
.marker = (struct addr_marker[]) {
{0, NULL},
{-1, NULL},
},
.level = -1,
.check_wx = true,
.ptdump = {
.note_page = note_page,
.range = (struct ptdump_range[]) {
{KERN_VIRT_START, ULONG_MAX},
{0, 0}
}
}
};
ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
if (st.wx_pages)
pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n",
st.wx_pages);
else
pr_info("Checked W+X mappings: passed, no W+X pages found\n");
}
static int ptdump_show(struct seq_file *m, void *v)
{
ptdump_walk(m, m->private);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump);
static int __init ptdump_init(void)
{
unsigned int i, j;
address_markers[FIXMAP_START_NR].start_address = FIXADDR_START;
address_markers[FIXMAP_END_NR].start_address = FIXADDR_TOP;
address_markers[PCI_IO_START_NR].start_address = PCI_IO_START;
address_markers[PCI_IO_END_NR].start_address = PCI_IO_END;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
address_markers[VMEMMAP_END_NR].start_address = VMEMMAP_END;
#endif
address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
address_markers[PAGE_OFFSET_NR].start_address = PAGE_OFFSET;
#ifdef CONFIG_KASAN
address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
#endif
#ifdef CONFIG_64BIT
address_markers[MODULES_MAPPING_NR].start_address = MODULES_VADDR;
address_markers[KERNEL_MAPPING_NR].start_address = kernel_map.virt_addr;
#endif
kernel_ptd_info.base_addr = KERN_VIRT_START;
pg_level[1].name = pgtable_l5_enabled ? "P4D" : "PGD";
pg_level[2].name = pgtable_l4_enabled ? "PUD" : "PGD";
for (i = 0; i < ARRAY_SIZE(pg_level); i++)
for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
pg_level[i].mask |= pte_bits[j].mask;
debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info,
&ptdump_fops);
#ifdef CONFIG_EFI
if (efi_enabled(EFI_RUNTIME_SERVICES))
debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info,
&ptdump_fops);
#endif
return 0;
}
device_initcall(ptdump_init);
|